User blog comment:KanameTousen/Delete a page?/@comment-2068382-20120520133352/@comment-1164563-20120521064631

It didn't "auto-detect" category in your post. There is no such thing there really. You accidentally transcluded the template instead of linking to it, which added the category to your post. "Transclusion" is when you link a template like this:. Transclusion adds all content from the transcluded page - in this case, Template:DMC2m. (Unless you use,   and/or  , but that's another talk.) I used a "wrapper" template to add a link to the template, T.

If interested or confused by my explanation, read more here and here